diff --git a/.changeset/config.json b/.changeset/config.json
index caead5d..bb66bd8 100644
--- a/.changeset/config.json
+++ b/.changeset/config.json
@@ -7,5 +7,8 @@
   "access": "public",
   "baseBranch": "main",
   "updateInternalDependencies": "patch",
-  "ignore": ["oidc-devtools", "@wolfcola/e2e", "@wolfcola/devtools-ui"]
+  "ignore": ["oidc-devtools", "@wolfcola/e2e", "@wolfcola/devtools-ui"],
+  "privatePackages": {
+    "version": true
+  }
 }
diff --git a/.changeset/sync-manifest-version.md b/.changeset/sync-manifest-version.md
new file mode 100644
index 0000000..0f11bac
--- /dev/null
+++ b/.changeset/sync-manifest-version.md
@@ -0,0 +1,7 @@
+---
+'@wolfcola/devtools-extension': patch
+---
+
+Automate manifest.json version sync: after `changeset version` bumps
+package.json, the new `sync-manifest` CLI copies the version into
+manifest.json so Chrome Web Store publishes show real version numbers.
diff --git a/docs/superpowers/specs/2026-05-12-changeset-sync-manifest-design.md b/docs/superpowers/specs/2026-05-12-changeset-sync-manifest-design.md
new file mode 100644
index 0000000..b787b96
--- /dev/null
+++ b/docs/superpowers/specs/2026-05-12-changeset-sync-manifest-design.md
@@ -0,0 +1,62 @@
+# @wolfcola/changeset-sync-manifest Design
+
+**Problem:** The Chrome extension `manifest.json` version is hardcoded at `0.1.0` and never bumped by changesets. Every CWS publish overwrites the same display version.
+
+**Solution:** A small CLI package that runs after `changeset version` and copies the `package.json` version into `manifest.json` for a given package directory.
+
+## Package
+
+- **Name:** `@wolfcola/changeset-sync-manifest`
+- **Location:** `packages/changeset-sync-manifest`
+- **Private:** yes
+
+### Files
+
+| File                   | Purpose                                                              |
+| ---------------------- | -------------------------------------------------------------------- |
+| `package.json`         | Package manifest with `bin` entry                                    |
+| `bin/sync-manifest.js` | Compiled CLI entry point                                             |
+| `src/sync.ts`          | Pure function: read `package.json` version, write to `manifest.json` |
+| `src/sync.test.ts`     | Unit tests                                                           |
+
+### CLI Interface
+
+```
+sync-manifest <dir>
+```
+
+- `<dir>` — path to a package directory containing both `package.json` and `manifest.json`
+- Reads `<dir>/package.json` → extracts `version`
+- Reads `<dir>/manifest.json` → sets `version` field → writes back
+- Exits non-zero if either file is missing or JSON is malformed
+
+### Pure Function
+
+```ts
+syncManifestVersion(dir: string): void
+```
+
+Reads `package.json` and `manifest.json` from `dir`, copies the version, writes `manifest.json` back with the updated version. Preserves existing formatting (2-space indent, trailing newline).
+
+## Integration
+
+### Changesets config (`.changeset/config.json`)
+
+- Add `"privatePackages": { "version": true }` so changesets bumps private packages
+- Remove `@wolfcola/devtools-extension` from `ignore` so it participates in the `@wolfcola/*` fixed group
+
+### Version script (root `package.json`)
+
+```
+"version": "changeset version && sync-manifest packages/devtools-extension && prettier --write '**/package.json' pnpm-workspace.yaml"
+```
+
+### Build pipeline (unchanged)
+
+`build.mjs` continues reading `manifest.json` and calling `stampVersion()` to append the CI build number as the 4th version segment. The only difference is that the base version in `manifest.json` now reflects the real package version instead of a hardcoded `0.1.0`.
+
+## What this does NOT do
+
+- Does not handle the VS Code extension (its `package.json` is its manifest — changesets handles it directly if removed from `ignore`)
+- Does not scan the workspace automatically — takes an explicit directory argument
+- Does not handle jsonpath or arbitrary file targets — just `package.json` → `manifest.json` version sync
diff --git a/package.json b/package.json
index 26d089d..0920d65 100644
--- a/package.json
+++ b/package.json
@@ -20,7 +20,7 @@
     "test": "vitest run",
     "typecheck": "tsc --build",
     "changeset": "changeset",
-    "version": "changeset version && prettier --write '**/package.json' pnpm-workspace.yaml",
+    "version": "changeset version && sync-manifest packages/devtools-extension && prettier --write '**/package.json' pnpm-workspace.yaml",
     "release": "pnpm build && changeset publish",
     "syncpack:lint": "syncpack lint",
     "syncpack:fix": "syncpack fix-mismatches",
@@ -45,6 +45,7 @@
     "syncpack": "^15.1.2",
     "typescript": "5.8.3",
     "vite": "catalog:vite",
+    "@wolfcola/changeset-sync-manifest": "workspace:*",
     "vitest": "catalog:vitest"
   },
   "pnpm": {
diff --git a/packages/changeset-sync-manifest/package.json b/packages/changeset-sync-manifest/package.json
new file mode 100644
index 0000000..903b785
--- /dev/null
+++ b/packages/changeset-sync-manifest/package.json
@@ -0,0 +1,24 @@
+{
+  "name": "@wolfcola/changeset-sync-manifest",
+  "version": "0.0.0",
+  "description": "Sync package.json version into manifest.json after changeset version",
+  "license": "MIT",
+  "type": "module",
+  "private": true,
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/ryanbas21/devtools.git",
+    "directory": "packages/changeset-sync-manifest"
+  },
+  "bin": {
+    "sync-manifest": "./dist/bin.js"
+  },
+  "scripts": {
+    "build": "tsc -p tsconfig.lib.json",
+    "lint": "eslint .",
+    "test": "vitest run"
+  },
+  "devDependencies": {
+    "vitest": "catalog:vitest"
+  }
+}
diff --git a/packages/changeset-sync-manifest/src/bin.ts b/packages/changeset-sync-manifest/src/bin.ts
new file mode 100644
index 0000000..bba8e03
--- /dev/null
+++ b/packages/changeset-sync-manifest/src/bin.ts
@@ -0,0 +1,18 @@
+#!/usr/bin/env node
+import { resolve } from 'node:path';
+import { syncManifestVersion } from './sync.js';
+
+const dir = process.argv[2];
+
+if (!dir) {
+  console.error('Usage: sync-manifest <dir>');
+  process.exit(1);
+}
+
+try {
+  syncManifestVersion(resolve(dir));
+  console.log(`Synced manifest.json version in ${dir}`);
+} catch (e) {
+  console.error(String(e instanceof Error ? e.message : e));
+  process.exit(1);
+}
diff --git a/packages/changeset-sync-manifest/src/sync.test.ts b/packages/changeset-sync-manifest/src/sync.test.ts
new file mode 100644
index 0000000..e311771
--- /dev/null
+++ b/packages/changeset-sync-manifest/src/sync.test.ts
@@ -0,0 +1,75 @@
+import { mkdtempSync, writeFileSync, readFileSync, rmSync } from 'node:fs';
+import { join } from 'node:path';
+import { tmpdir } from 'node:os';
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { syncManifestVersion } from './sync.js';
+
+describe('syncManifestVersion', () => {
+  let dir: string;
+
+  beforeEach(() => {
+    dir = mkdtempSync(join(tmpdir(), 'sync-manifest-'));
+  });
+
+  afterEach(() => {
+    rmSync(dir, { recursive: true, force: true });
+  });
+
+  it('copies version from package.json to manifest.json', () => {
+    writeFileSync(join(dir, 'package.json'), JSON.stringify({ version: '2.0.0' }));
+    writeFileSync(
+      join(dir, 'manifest.json'),
+      JSON.stringify({ manifest_version: 3, version: '0.1.0' }),
+    );
+
+    syncManifestVersion(dir);
+
+    const manifest = JSON.parse(readFileSync(join(dir, 'manifest.json'), 'utf8'));
+    expect(manifest.version).toBe('2.0.0');
+  });
+
+  it('preserves other manifest fields', () => {
+    writeFileSync(join(dir, 'package.json'), JSON.stringify({ version: '1.0.0' }));
+    writeFileSync(
+      join(dir, 'manifest.json'),
+      JSON.stringify({ manifest_version: 3, name: 'My Extension', version: '0.1.0' }),
+    );
+
+    syncManifestVersion(dir);
+
+    const manifest = JSON.parse(readFileSync(join(dir, 'manifest.json'), 'utf8'));
+    expect(manifest.manifest_version).toBe(3);
+    expect(manifest.name).toBe('My Extension');
+    expect(manifest.version).toBe('1.0.0');
+  });
+
+  it('writes with 2-space indent and trailing newline', () => {
+    writeFileSync(join(dir, 'package.json'), JSON.stringify({ version: '1.0.0' }));
+    writeFileSync(join(dir, 'manifest.json'), JSON.stringify({ version: '0.1.0' }));
+
+    syncManifestVersion(dir);
+
+    const raw = readFileSync(join(dir, 'manifest.json'), 'utf8');
+    expect(raw).toContain('  "version"');
+    expect(raw.endsWith('\n')).toBe(true);
+  });
+
+  it('throws if package.json is missing', () => {
+    writeFileSync(join(dir, 'manifest.json'), JSON.stringify({ version: '0.1.0' }));
+
+    expect(() => syncManifestVersion(dir)).toThrow('package.json');
+  });
+
+  it('throws if manifest.json is missing', () => {
+    writeFileSync(join(dir, 'package.json'), JSON.stringify({ version: '1.0.0' }));
+
+    expect(() => syncManifestVersion(dir)).toThrow('manifest.json');
+  });
+
+  it('throws if package.json has no version field', () => {
+    writeFileSync(join(dir, 'package.json'), JSON.stringify({ name: 'test' }));
+    writeFileSync(join(dir, 'manifest.json'), JSON.stringify({ version: '0.1.0' }));
+
+    expect(() => syncManifestVersion(dir)).toThrow('version');
+  });
+});
diff --git a/packages/changeset-sync-manifest/src/sync.ts b/packages/changeset-sync-manifest/src/sync.ts
new file mode 100644
index 0000000..530acdd
--- /dev/null
+++ b/packages/changeset-sync-manifest/src/sync.ts
@@ -0,0 +1,31 @@
+import { readFileSync, writeFileSync } from 'node:fs';
+import { join } from 'node:path';
+
+export const syncManifestVersion = (dir: string): void => {
+  const pkgPath = join(dir, 'package.json');
+  const manifestPath = join(dir, 'manifest.json');
+
+  let pkgRaw: string;
+  try {
+    pkgRaw = readFileSync(pkgPath, 'utf8');
+  } catch {
+    throw new Error(`Cannot read package.json at ${pkgPath}`);
+  }
+
+  let manifestRaw: string;
+  try {
+    manifestRaw = readFileSync(manifestPath, 'utf8');
+  } catch {
+    throw new Error(`Cannot read manifest.json at ${manifestPath}`);
+  }
+
+  const pkg = JSON.parse(pkgRaw) as { version?: string };
+  if (!pkg.version) {
+    throw new Error(`No version field in ${pkgPath}`);
+  }
+
+  const manifest = JSON.parse(manifestRaw) as Record<string, unknown>;
+  manifest.version = pkg.version;
+
+  writeFileSync(manifestPath, JSON.stringify(manifest, null, 2) + '\n');
+};
diff --git a/packages/changeset-sync-manifest/tsconfig.json b/packages/changeset-sync-manifest/tsconfig.json
new file mode 100644
index 0000000..f6a4a19
--- /dev/null
+++ b/packages/changeset-sync-manifest/tsconfig.json
@@ -0,0 +1,19 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "dist",
+    "tsBuildInfoFile": "dist/tsconfig.tsbuildinfo",
+    "module": "nodenext",
+    "moduleResolution": "nodenext",
+    "verbatimModuleSyntax": true,
+    "forceConsistentCasingInFileNames": true,
+    "strict": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "types": ["node"]
+  },
+  "include": ["src/**/*.ts"],
+  "references": [],
+  "exclude": ["vitest.config.mts", "src/**/*.test.ts"]
+}
diff --git a/packages/changeset-sync-manifest/tsconfig.lib.json b/packages/changeset-sync-manifest/tsconfig.lib.json
new file mode 100644
index 0000000..2d042cc
--- /dev/null
+++ b/packages/changeset-sync-manifest/tsconfig.lib.json
@@ -0,0 +1,6 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "emitDeclarationOnly": false
+  }
+}
diff --git a/packages/changeset-sync-manifest/vitest.config.mts b/packages/changeset-sync-manifest/vitest.config.mts
new file mode 100644
index 0000000..b107878
--- /dev/null
+++ b/packages/changeset-sync-manifest/vitest.config.mts
@@ -0,0 +1,14 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig(() => ({
+  root: __dirname,
+  cacheDir: '../../node_modules/.vite/packages/changeset-sync-manifest',
+  test: {
+    name: 'changeset-sync-manifest',
+    watch: false,
+    globals: true,
+    environment: 'node',
+    include: ['{src,tests}/**/*.{test,spec}.{js,mjs,cjs,ts,mts,cts,jsx,tsx}'],
+    reporters: ['default'],
+  },
+}));
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 7139fce..e2e6ad5 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -63,6 +63,9 @@ importers:
       '@typescript-eslint/parser':
         specifier: ^8.45.0
         version: 8.59.2(eslint@9.39.4)(typescript@5.8.3)
+      '@wolfcola/changeset-sync-manifest':
+        specifier: workspace:*
+        version: link:packages/changeset-sync-manifest
       eslint:
         specifier: ^9.8.0
         version: 9.39.4
@@ -137,6 +140,12 @@ importers:
         specifier: catalog:vitest
         version: 3.2.4(@types/node@22.19.18)(jsdom@26.1.0)(terser@5.47.1)(yaml@2.9.0)
 
+  packages/changeset-sync-manifest:
+    devDependencies:
+      vitest:
+        specifier: catalog:vitest
+        version: 3.2.4(@types/node@22.19.18)(jsdom@26.1.0)(terser@5.47.1)(yaml@2.9.0)
+
   packages/devtools-bridge:
     dependencies:
       '@forgerock/davinci-client':
diff --git a/tsconfig.json b/tsconfig.json
index 91b66bc..3840608 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -7,6 +7,7 @@
     { "path": "packages/devtools-extension" },
     { "path": "packages/vscode-extension" },
     { "path": "packages/treeshake-check" },
-    { "path": "packages/eslint-plugin-treeshake" }
+    { "path": "packages/eslint-plugin-treeshake" },
+    { "path": "packages/changeset-sync-manifest" }
   ]
 }